In the case of fundamentally known air spring modules having a plurality of working chambers, each having a volume (volume V1 to Vi), individual volumes (Vgesamt=ΣVi) must be divided from the overall air spring volume by a partition wall and suitable switching valves.
Thus, an air spring having two working chambers can be found in DE 102 00 632 A1, which is incorporated by reference, for example, wherein the second working chamber is designed with an additional volume in the air spring cover, making it possible to switch between a sporty or a comfortable mode of the air spring module by connecting or disconnecting the additional volume.
In contrast, more recent air spring developments have three volumes, thus making it possible to select one or two intermediate modes between sport and comfort.
In the case of these three volumes, additional volumes 1 and 2 can be separated off, ensuring that only V0 (=air spring) exhibits a spring action. If valve 1 is opened, additional volume 1 is added and volumes V0+ZV1 are available. If, on the other hand, valve 2 is opened, volumes V0+ZV2 are available. If both valves are open, volumes V0+ZV1+ZV2 are available. Thus, the overall volumes V0, V0+ZV1, V0+ZV2 and V0+ZV1+ZV2 can be selected. Through appropriate selection of the size of the additional volumes, it is thus possible to implement very finely graduated volumes and thus also spring rates.
Here, the small volume V0 on its own gives a sporty and hard spring rate, while the large volume V0+ZV1+ZV2 gives a comfortable and soft spring rate.
The principle involving air spring volumes plus two additional volumes is already known. However, in that case the two additional volumes and valves are integrated into the cover. Particularly as regards available installation space, which is generally small, this embodiment has disadvantages. Moreover, it leads to high costs, production outlay and assembly effort.